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Have you read the previous of digestive system part 1? We will move on talking about the roles of enzymes and alimentary canal in this post! 😁
The roles of enzymes:
- Carbohydrase digest carbohydrates, e.g. Amylase digests starch to simple sugars
- Proteases digest proteins to amino acids
- Lipases digest fats to fatty acids and glycerol
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/601456_286540.jpeg)
Biles
In I/GCSE Biology, it's important to memorize how bile functions in the exam!
- Bile is added in the small intestine to neutralise stomach acid.
- This means that the enzymes in the stomach can work at their optimum pH.
- Bile also emulsifies (break up large drops of fat into smaller droplets that remain mixed in a watery liquid) fats so that there is a greater surface area for lipases to work on.
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/302427_859700.png)
Alimentary canal
a muscular tube running from the mouth to the anus.
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/961112_964021.jpeg)
Villi
- One villus / many villi.
- The large capillary network carries absorbed molcules away quickly
- maintain a steep concentration gradient for diffusion.
- Millions of villi means an increased surface area.
- The surface is formed from a single layer of cells making diffusion easier.
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/539277_601725.png)
Last but not least, you should know the following points in I/GCSE Biology as well!
Probiotics and Prebiotics
Functional foods are food that claim to make you healthier when you eat them.
Probiotics:
- Contain friendly bacteria
- Little scientific evidence to support that it improves your digestive and immune system
Prebiotics:
- Contain high levels of oligosaccharides
- Scientific evidence of them improving health by reducing the risk of diarrhoea
Plant stanol esters:
- Reduce the amount of chlolesterol absorbed from digested food
- May reduce risk of heart disease
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/954095_858716.png)
And we're done with this topic! Well Done!
![broken image](http://custom-images.strikinglycdn.com/res/hrscywv4p/image/upload/c_limit,fl_lossy,h_9000,w_1200,f_auto,q_auto/4936730/737825_704486.png)
Drafted by Alyssa (Biology)
References:
- "B2 - Enzymes", https://images.slideplayer.com/12/3396173/slides/slide_6.jpg
- "What Is the Function of Bile?", https://images.medicinenet.com/images/article/main_image/what-is-the-function-of-bile.jpg
- "gastrointestinal tract", https://cdn.britannica.com/39/8039-050-84745FFB/human-digestive-system-front.jpg
- "Villi in the small intestine". Photo from the internet.
- "Probiotics and Prebiotics as Functional Foods: State of the Art | Bentham Science". Photo from the internet.